Posted now on the Regent website:

What is the dress code onboard the ships?

Attire ranges from Casual to Formal Optional. Casual wear is appropriate for daytime onboard or ashore, and consists of resort-style outfits. Casual wear, including shorts and jeans, is not appropriate after 6:00 pm, with the exception of the final evening of the cruise. On the night prior to disembarkation, guests may need to pack their luggage early due to morning flights the next day. With this in mind on the last night of every voyage we will relax the dress code for dinner to Casual.[u][/u]

Also, on cruise critic a poster now on board the Mariner said the Hostess in the new venue, Setti Mari told him after he saw three men in jeans at dinner, that they jeans are OK as they are promoting a more casual atmosphere.

Within the hour asked Mark Conroy about jeans in Setti Mari, his reply:

From: "Mark Conroy"
To: Colonelretwes
Sent: Wednesday, July 18, 2012 5:36:59 PM
Subject: RE: thanks

We don’t promote it that way but I think jeans are ok there it was always the one very casual venue.


Mark

Mark S. Conroy │ President
Regent Seven Seas Cruises
8300 NW 33rd Street │Suite 100